The Food and Drug Administration said that it had discovered the toxic chemical melamine in infant formula made by an American manufacturer.
Agency officials said they had discovered melamine at trace levels in a sample of infant formula. It was also discovered in several samples of dietary supplements that are made by some of the same manufacturers who make formula.
Melamine contamination became a major scandal in China after it was added to milk to disguise test results that measure protein levels. Since it was discovered in infant formula in September, it has sickened more than 50,000 infants and killed 4.